The planktonic prokaryotic microorganisms diversity and composition impact on environmental restoration and ecological processes in estuarine ecosystem therefore, investigating the factors that influence planktonic prokaryotic microorganisms biodiversity is critical to addressing urgent questions related to environmental pollution and ecological deterioration. In this study, we assessed the diversity and distribution of prokaryotic microbial community in 24 water samples collected from eight major outlets in Pearl River, South China, by using Illumina Hiseq sequencing targeting the 16S rRNA V4 region